Use an assist
if single leg balance is an issue and gradually reduce assistance until you can perform the drill with confidence while minimizing any superfluous movement.
The stork balance is a
simple single leg balance exercise, although various progressions can be added to make it more difficult.
Single leg balance or performing a plank.
A few of the exercises I do include: planks,
single leg balance, ball crunches, single leg squat, cable rotations and single leg deadlifts.
The medicine ball catch exercise is designed to challenge
the single leg balance with an unknown.